1. Field of Invention
This invention relates to scuba diving weight ballast systems used for buoyancy control and scuba tank stability.
2. Description of Prior Art
When scuba diving a diver must add negative weight ballast to his body and or equipment in order to descend below the surface of the water. The prior art form of negative ballast is normally a waist worn weight belt. This weight belt is usually left on the divers waist from the time he enters and exits the water. The weight belt adds a significant amount of "dead weight" to the diving equipment. This dead weight makes it difficult for a diver to exit the water and climb back into a boat while ocean diving. The one piece (waist worn) weight belts generally are to heavy and awkward to remove and install in the water. It takes two hands to attach the weight belt around the waist. It is almost impossible to attach the belt while floating in the water. This prior art form also makes it difficult for a diver to stand and walk erect while beach diving or getting into the equipment on a pitching boat. The diver must lean forward (hunch backed) to counterbalance the weight of the scuba tank which is pulling him backwards.
The traditional art form (waist worn weight belts) also rub and bang against the divers hips while making ascents and descents. This has a tendency to make diving uncomfortable. This art form also places the divers body in tension because the weights are pulling him down from the waist while the buoyancy compensator is lifting him up from the shoulders and upper torso. This causes undue muscle fatigue.
Getting into the scuba diving tank on a pitching boat while ocean diving can be very difficult for a scuba diver. The scuba tank and attached related equipment generally have a very high center of gravity. The tank itself has a small circular bottom which does not provide good stabilty in the upright position while a diver is getting into the equipment. It is not unusual that a diver must have help to get into the equipment under these conditions. An assistant must hold the tank steady while the diver gets into the shoulder and waist straps to secure the tank to his body.
Several different types of tank mounted weight ballast systems have been proposed- for example U.S. Pat. No. 3,967,459 (1961) to Denis and U.S. Pat. No. 4,455,718 (1984) to Finnern. Although this prior art does propose a way to add ballast to the frame or scuba tank, most of these designs suffer from the following disadvantages:
a. Ballast weights generally can only be released when the tank is in the vertical position.
b. The release mechanism is in an awkward position that may be impossible for a diver to see and reach.
c. Only one release mechanism is provided with no secondary or "fail safe" independent backup system.
d. The ballast weights are not positioned with a "systems engineering" approach to counterbalance undesirable moments and forces.
e. None of the prior art shows an attempt to use the ballast weights for secondary purposes such as providing vertical tank stability to aid the diver while getting into the equipment.
f. None of the prior art adds weight ballast below the divers center of gravity in the horizontal plane (keel ballast) to give him roll stability.
g. All of the prior art form suspends the scuba tank weight on the divers shoulders giving him a high and unstable center of gravity out of the water.
h. Previous art form releases all of the ballast weight at one time in emergency conditions.